BQ40Z50 Datasheet, PDF (20/30 Pages) Texas Instruments – 1-Series, 2-Series, 3-Series, and 4-Series Li-Ion Battery Pack Manager

bq40z50
SLUSBS8 – DECEMBER 2013
• Data Flash Permanent Failure
• Open Thermistor Permanent Failure
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Charge Control Features
The bq40z50 charge control features include:
• Supports JEITA temperature ranges. Reports charging voltage and charging current according to the active
temperature range
• Handles more complex charging profiles. Allows for splitting the standard temperature range into two sub-
ranges and allows for varying the charging current according to the cell voltage
• Reports the appropriate charging current needed for constant current charging and the appropriate charging
voltage needed for constant voltage charging to a smart charger using SMBus broadcasts
• Reduces the charge difference of the battery cells in fully charged state of the battery pack gradually using a
voltage-based cell balancing algorithm during charging. A voltage threshold can be set up for cell balancing to
be active. This prevents fully charged cells from overcharging and causing excessive degradation and also
increases the usable pack energy by preventing premature charge termination.
• Supports pre-charging/zero-volt charging
• Supports charge inhibit and charge suspend if battery pack temperature is out of temperature range
• Reports charging fault and also indicates charge status via charge and discharge alarms
Gas Gauging
The bq40z50 uses the Impedance Track algorithm to measure and calculate the available capacity in battery
cells. The bq40z50 accumulates a measure of charge and discharge currents and compensates the charge
current measurement for the temperature and state-of-charge of the battery. The bq40z50 estimates self-
discharge of the battery and also adjusts the self-discharge estimation based on temperature. The device also
has TURBO BOOST mode support, which enables the bq40z50 to provide the necessary data for the MCU to
determine what level of peak power consumption can be applied without causing a system reset or transient
battery voltage level spike to trigger termination flags. See the bq40z50 Technical Reference Manual (SLUUA43)
for further details.
Battery Trip Point (BTP)
Required for WIN8 OS, the battery trip point (BTP) feature indicates when the RSOC of a battery pack has
depleted to a certain value set in a DF register. This feature allows a host to program two capacity-based
thresholds that govern the triggering of a BTP interrupt on the BTP_INT pin and the setting or clearing of the
OperationStatus[BTP_INT] on the basis of RemainingCapacity().
An internal weak pull-up is applied when the BTP feature is active. Depending on the system design, an external
pull-up may required to put on the BTP_INT pin. See PRES, BTP_INT, DISP for details.
Lifetime Data Logging Features
The bq40z50 offers lifetime data logging for several critical battery parameters. The following parameters are
updated every 10 hours if a difference is detected between values in RAM and data flash:
• Maximum and Minimum Cell Voltages
• Maximum Delta Cell Voltage
• Maximum Charge Current
• Maximum Discharge Current
• Maximum Average Discharge Current
• Maximum Average Discharge Power
• Maximum and Minimum Cell Temperature
• Maximum Delta Cell Temperature
• Maximum and Minimum Internal Sensor Temperature
• Maximum FET Temperature
• Number of Safety Events Occurrences and the Last Cycle of the Occurrence
• Number of Valid Charge Termination and the Last Cycle of the Valid Charge Termination
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